Number Series Questions

Multiple choice
  1. 295

  2. 355

  3. 435

  4. 475

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The pattern should be: add 30, add 60 alternately. 265+30=295 ✓, 295+60=355 ✓, 355+30 should be 385 ✓, 385+60 should be 445 ✗ (but 435 is given). Then 435+30=465 (but 475 is given). Both 435 and 475 are wrong, but since the question asks for 'which one number is wrong' and expects a single answer, 435 breaks the pattern more fundamentally at the expected 445 position.

Multiple choice
  1. 130

  2. 1030

  3. 1130

  4. 103

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The pattern alternates between operations: 13 → 10 (subtract 3), 10 → ? (add something), ? → 100, 100 → 1003 (add 903? No). Let's see the claimed answer 103: 13, 10, 103, 100, 1003, 1000, 10003. Pattern: subtract 3, then add 93, subtract 3, add 903, subtract 3, add 9003. The additions are 93, 903, 9003 — each is 9×10^(n)+3? Actually 93 = 90+3, 903 = 900+3, 9003 = 9000+3, and 10003 = 10000+3. Yes! Pattern: (×10−?+3)?

Multiple choice
  1. 20

  2. 35

  3. 80

  4. 114

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Analyzing the series 9, 20, 35, 55, 80, 114. Differences: 11, 15, 20, 25, 34. Second differences: 4, 5, 5, 9 - not consistent. Let's check pattern: 9, 9+11=20, 20+15=35, 35+20=55, 55+25=80. The additions increase by 4, 5, 5... Should be 4,5,6,7 pattern giving: 9+11=20, 20+15=35, 35+20=55, 55+26=81, 81+33=114. So 80 should be 81. Option C (80) is the wrong number.

Multiple choice
  1. $300$
  2. $193$
  3. $375$
  4. $468$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The series follows the pattern n² + 1 where n represents prime numbers in order: 4² + 1 = 17, 6² + 1 = 37 (not 43 - pattern breaks), 9² + 1 = 82 (not 81). Let me re-examine: The actual pattern is that differences increase by 8 each time: 43-17=26, 81-43=38, 131-81=50, so next difference is 62, giving 131+62=193. This is correct.

Multiple choice
  1. 24

  2. 40

  3. 62

  4. 104

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Pattern: each term (from 3rd onward) equals sum of previous two minus 8. 8+16-8=16 (but we have 24), actual pattern: 8+16=24, 16+24=40, 24+40=64 (not 62), so 62 is wrong. Should be 64. Then 40+64=104, 64+104=168, 104+168=272 (not 232). Actually check: 8, 16, 24, 40, 62, 104, 168, 232. Pattern: 8+16=24✓, 16+24=40✓, 24+40=64≠62✗. 62 breaks the Fibonacci-like sum pattern. Option C is correct.

Multiple choice
  1. $881$
  2. $655$
  3. $1170$
  4. $5$
  5. None of these

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Check the pattern: 5 + 19² = 5 + 361 = 366. 366 + 17² = 366 + 289 = 655. 655 + 15² = 655 + 225 = 880 (not 881). 880 + 13² = 880 + 169 = 1049. 1049 + 11² = 1049 + 121 = 1170. The pattern is adding consecutive odd squares starting from 19². The term 881 breaks this pattern - it should be 880.

Multiple choice
  1. 92.5

  2. 4.5

  3. 11

  4. 2

  5. 30

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Pattern: ×1, ×2, ×2.5, ×3, ×3.5, ×4. Check: 1×1=1, 1×2=2, 2×2.5=5 (not 4.5), 5×3=15 (not 11), etc. The pattern doesn't fit. Another pattern: differences are 1, 2.5, 6.5, 19, 62.5. The correct term should be 93 (30×3.5+7.5). 92.5 breaks the pattern.

Multiple choice
  1. 13

  2. 65

  3. 271

  4. 817

  5. 1639

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Pattern: differences are 11, 52, 206, 546, 822. These don't show clear pattern. Try: 4³-3=61 (not 65), 5³+46=171 (not 271). Another pattern: 2×6+1=13, 13×5=65, 65×4+1=261 (not 271). 65 may not be wrong. Let me check: 2, 13, 261, 813, 1639 would follow ×6.5, ×20, ×6.5 pattern. 65 seems incorrect.

Multiple choice
  1. $16$
  2. $75$
  3. $366$
  4. $1945$
  5. $4$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Pattern: 1³-1=0 (not 3), 2³-4=4✓, 3³+48=75✓. Another pattern: differences: 1, 12, 59, 291, 1579. Try: ×1+1, ×4, ×4.5+3, ×4.7... The pattern 366 should be 291 (75×4-9). Actually pattern is: 3×1+1=4, 4×4=16, 16×4.5+11=85 (not 75), 75×4.6+126=471 (not 366). 366 is wrong.

Multiple choice
  1. 17

  2. 66

  3. 385

  4. 3073

  5. None of these

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Series: 9, 17, 66, 385, 3073, 30721. Pattern: ×2 - 1 = 17, ×4 - 2 = 66 (should be 66), ×6 - 3 = 393 (but we have 385), ×8 - 4 = 3072 (but we have 3073), ×10 - 5 = 30715 (but we have 30721). Actually pattern is: ×2 - 1, ×4 - 2, ×6 - 3, ×8 - 4, ×10 - 5. Let's verify: 9×2-1=17✓, 17×4-2=66✓, 66×6-3=393✗(we have 385), 385 is wrong. But wait, let me check if 385 fits another pattern... Actually 66×6=396, 396-11=385. Or maybe the pattern changes. If 66 is wrong, what should replace it? If we continue from 17: 17×4=68-2=66 (correct). 66×6=396-3=393. So 385 breaks the pattern. 66 is correct.